title: Cerebral toxoplasmosis in a middle-aged man as first presentation of primary immunodeficiency due to a hypomorphic mutation in the CD40 ligand gene.
abstract: Cerebral toxoplasmosis can occur outside the setting of advanced HIV immunodeficiency or drug-induced immunosuppression. A case of cerebral toxoplasmosis is reported in a previously healthy 41-year-old man who was found to have a genetic defect in CD40 ligand, resulting in the X linked hyper-IgM syndrome despite normal surface protein expression on flow cytometry. This highlights the fact that primary immunodeficiencies can first present late in life with a relatively mild phenotype and should be considered in the differential diagnosis of opportunistic infections in non-HIV infected patients; in addition, normal protein expression does not necessarily rule out hypomorphic mutations.
authors.affiliation: Department of Clinical Immunology, King's College Hospital, London, UK.
authors.forename: P F K
authors.initials: PF
authors.lastname: Yong
authors.forename: F A
authors.initials: FA
authors.lastname: Post
authors.forename: K C
authors.initials: KC
authors.lastname: Gilmour
authors.forename: D
authors.initials: D
authors.lastname: Grosse-Kreul
authors.forename: A
authors.initials: A
authors.lastname: King
authors.forename: P
authors.initials: P
authors.lastname: Easterbrook
authors.forename: M A A
authors.initials: MA
authors.lastname: Ibrahim
mesh_terms: D000328:Adult; D023201:CD40 Ligand / Q000097:blood / Q000235:genetics*; D006801:Humans; D053306:Hyper-IgM Immunodeficiency Syndrome / Q000150:complications* / Q000175:diagnosis / Q000235:genetics; D008279:Magnetic Resonance Imaging; D008297:Male; D009154:Mutation; D009894:Opportunistic Infections / Q000150:complications* / Q000175:diagnosis; D016781:Toxoplasmosis, Cerebral / Q000150:complications* / Q000175:diagnosis
chemical_list: D023201:CD40 Ligand